Degenerative disc disease or degeneration of a vertebral body often results in a loss of disc height, which in turn can cause facet and nerve impingement, among other things. One standard of care is to replace the damaged intervertebral disc with an intervertebral implant or a damaged portion or an entire vertebral body with an intervertebral implant.
Thus, an intervertebral implant may be inserted into the intervertebral disc space of two adjacent vertebral bodies or into the space created by removal of portions of, or the entire, vertebral body after removal of damaged portions of the spine. Preferably, the intervertebral implant restores the spine, as much as possible, to a natural state. That is, the implant preferably restores the original height of the intervertebral disc and thus the original distance between the two adjacent vertebral bodies or vertebral bodies in various levels of the spine. These implants are sized and shaped to fill at least the physiological height between the vertebral bodies and are inserted through a relatively narrow and small incision with nerves and vascular structure proximate sides of the incision. Accordingly, it is advantageous to develop an implant that may be inserted in a reduced size or configuration and expanded when positioned between the vertebrae to minimize the required incision and limit the potential for the implant to contact the neural and vascular structure during implantation.
It is desirable to construct an intervertebral implant that restores the spine to its natural state, is relatively compact during insertion and may be expanded when positioned between adjacent vertebrae. It is also desirable to construct an expandable intervertebral implant that may be inserted and expanded utilizing the same instrument.